1. Field
Aspects of the present invention relate to lithium air batteries.
2. Description of the Related Art
A lithium air battery generally includes a negative electrode capable of intercalating and deintercalating lithium ions, a positive electrode that oxidizes and reduces oxygen present in the air, and an electrolyte disposed between the negative and positive electrodes.
Since use of a lithium positive electrode makes it unnecessary to store air within a positive active material, the lithium air battery may have high capacity. Lithium air batteries have a high theoretical energy density per unit weight of 3500 Wh/kg or greater, which are about ten times higher than that of lithium ion batteries. However, because of polarization by a high overvoltage during charging and discharging, existing lithium air batteries have considerably low energy efficiency compared to lithium ion batteries.
To lower the charge-discharge overvoltage, various kinds of catalysts have been used; however, their effect has not been sufficient. Therefore, there is a demand for methods to further reduce the charge-discharge overvoltage for obtaining higher charge-discharge energy efficiency.